/*
 *  Copyright 2008-2009 NVIDIA Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
    
#include <sfv/format.h>
#include <sfv/array1d.h>

namespace sfv
{
namespace detail
{

template <typename OffsetArray, typename IndexArray>
void offsets_to_indices(const OffsetArray& offsets, IndexArray& indices)
{
    typedef typename OffsetArray::value_type OffsetType;

	for( size_t row = 0; row < offsets.size()-1; row++ )
	{
		OffsetType row_start = offsets[row];
		OffsetType row_end   = offsets[row+1];

		for( OffsetType i = row_start; i < row_end; i++ )
			indices[i] = row;
	}
}

template <typename IndexArray, typename OffsetArray>
void indices_to_offsets(const IndexArray& indices, OffsetArray& offsets)
{
    typedef typename IndexArray::value_type IndexType;

	for( size_t i = 0; i < offsets.size(); i++ )
		offsets[i] = 0;

	for( size_t i = 0; i < indices.size(); i++ )
	{
		IndexType index = indices[i];
		offsets[index+1]++;
	}

	for( size_t i = 0; i < offsets.size()-1; i++ )
		offsets[i+1] += offsets[i];
}

} // end namespace detail
} // end namespace sfv
